Is Increased Mortality from Alzheimers Disease in Sweden a Reflection of Better Diagnostics?

Abstract

Mortality data were retrieved from the Swedish death registry for the years 1970-2006. This report presents updated information on mortality from Alzheimer's disease (AD) through the year 2006, as well as a statistical model of AD mortality with predictive value. This model was developed based on a mortality risk function acting after a specific time point, either step-wise on the whole population or on an increasing part of it. Data collected in recent years indicate that mortality is increasing continuously amongst the oldest patients, while younger age-groups show more stable mortality rates. After fitting the statistical model to age-standardized mortality data it also gave age-specific rates that fit well with reported data without further adjustments in model parameters. The data and the corresponding model for AD mortality suggest that the ability of the body to protect itself from AD-related neurological damage has in general became increasingly impaired since about 1985. This impairment has mainly affected people 65 years of age and older since 1985; the model predicts that in 2020, the age-standardized mortality in Sweden will be 13/100,000 person-years. The author concludes that the increasing mortality is real and not only a result of increasing use of the death classification code for AD.